A few notes.

Part of the justification for the mostly-solid A6 was its commonality with the SRB's on the Vega, which is already flying.

Part of the A5 problem is that the upper stage is not relightable. This means that when Ariane try to get 2 sats to launch together they have to close to the same part of the GEO orbit.

While I can sort of understand this for the LH2/LO2 US Astus propellants are hypergolic and ignite on contact.

The other issue is that sat weights have been creeping up and getting a heavy + medium weight pair together is getting harder. However the payload rise is not beyond the bounds of an upgrade starting with the Vehicle Equipment Bay . This thing is in carbon fibre and is less than 1/2 the diameter and no taller than the one on the Saturn V (whose computer weighted about 50Kg and whose gyros weighed another 50Kg without the GN2 to spin them up) yet it weighs the same (the Saturn one was built in Al honeycomb by IBM, not a company known for their light weight structures engineering). The Saturn V Instrument Unit was also designed to carry a 100 tonne Apollo stack on top.

The proudest boast some politicians want to make.

Note the part about *existing* fibre, not tricky stuff with FO ampliers.

There's a lot of that in the ground/ocean already and replacing a bunch of repeaters with basically a short length of passive fibre (if you can't pull one of them through into the chamber and join them directly) is going to save some people a very great deal of money.

The early 90's are back. Yay

Several companies tried various rifts on the LEO (or MEO) comms game back then. I think there were about 5 of them with proposals.

Several RLV companies thought this was the killer app.

IIRC only Orbcomm (SMS from space, OK for tracking long distance truck drivers) and Iridium (very expensive calls to oil exploration workers in the field, later the DoD) actually launched. Both are on their 2nd (or 3rd) generations.

The RLV companies just died.

There is some speculation that this will be the application that needs all those reusable F9 1st stages that SpaceX is hoping to recover and refurbish over the coming years.

What's that? the product is complaining.

Re: Jovial mainframe compilers.

"As someone who has been around DEC kit being used for safety related stuff in UK for three decades (either as development host, or target platform (eg European Air Traffic Control), or both) I can safely say that although I encountered several instances of Coral and a handful of RTL/2, I came across writeups of the language but never came across a real Jovial, host or target, and I'm not aware that any of my US colleagues did either. [Iirc, a few of the Coral applications started with 'BEGIN CORAL; BEGIN CODE;' followed by in-line assembler for the remainder of the application]"

For a more complete list of JOVIAL apps (and development hosts) can be found here.

Re: There's legacy, and there's legacy

"RTL2 was another matter. It seemed to incorporate the worst features of C and Pascal, with none of their redeeming characteristics, and a buggy compiler to boot. I remember compiling RTL2 to PDP11 assembler, and then having to get the overlays right to fit it all into 48K. Building got easier when the output was M68K, the compiler was no less buggy though."

AFAIK RTL/2 predates C and is around the same age as Pascal.

One of Unix's lesser appreciated gifts to the world was putting YACC and lex into the hands of anyone who wanted them. Suddenly if you wanted a compiler (and where prepared to invest a relatively small amount of time) you could have it

Before that if you wanted a compiler it was fire up the assembler, and prepare for pain. I would suspect that RTL/2 (like early C) didn't really have a formal "standard" and at any given moment they either hacked the compiler to match the (desired) behavior or hacked the standard to formalize what the compiler could do (without massive surgery to its structure).

With "hilarious" consequences all round.

Keep in mind that the "classic" PDP 11s did not have memory management hardware (IIRC that came with the 11/780s and the VAX's ).

BTW the British Teletext systems ran on PDP 11's running RTL/2 code before being retired in a C rewrite.

Re: There's legacy, and there's legacy

"These days gcc and gnat mean that in general 'only' the code generating bits need to be target specific, other kind and clever people have done most of the rest in a target-independent fashion, and you can have it (source included) for free."

Unfortunately the problem is not that you have a good compiler (Which is maybe 1/3 the problem. You need versions of the Ada standard packages and some version of the defined Ada development environment, ideally tools using the DIANA intermediate language.

But you're still not done.

You have to prove it. That's where you need a certified Ada validation suite from someone like NIST or BSI to prove what your compiler does (and does not) compile meets the Ada standard exactly

Do I have to say you won't find one of these on the shelves at PC World?

It's about giving the customer the certainty that the customers code will do exactly what the standard says it will do (although wheather they realize exactly what that is is another matter).

I know. It's anal, it's bureaucratic, it's slow but it's how they roll.

And honestly if you're sitting in one of those metal tubes in the sky would you really have it any other way?

Re: There's nothing like state of the art hardware

"OS/370 and its descendants were running mission critical workdwide apps when you were in nappies boy. "

Could you say with an "Emperor Palpatine" voice?

For the more humor impaired in the audience I should say I absolutely agree. I wonder if this is the one they got off the FAA in the states, and does it still have valves in it, as their last one is reputedly said to have had.

Reading the story and the comments 2 things intrigue me.

1) It looks like it was a "bug" in the data that borked the primary, then it did the secondary, which tried to switch back to the primary. So what kind of data can't be sanity checked before its passed into the system (and of course will checking be added to the code now)?

2) I did not know a Jovial compiler for IBM mainframes even existed. Historically it's been for deep embedded systems like aircraft flight computers, ECM systems, radars etc.

Re: There's legacy, and there's legacy

"But I've not kept abreast of recent developments, so does any one know what is now being used instead of JOVIAL? (I'm a little surprised the wikipedia article doesn't mention this, so presume the obvious candidate - ADA, isn't quite so obvious or universally used)."

JOVIAL was big for real time control apps. IIRC it did the software for the B52, B1 and F15 at least (off the top of my head). The USN (being the USN) had something else (CSL?, something with a C in it)

I guess the UK equivalent were things like CORAL66 and RTL2 (ICI's in house computer language. No that's not a typo).

In theory Ada was meant to be the cure for this babel of DoD languages (including most of the assembler). But writing a full Ada compiler is a not trivial exercise and the DoD has a lot of odd hardware knocking about. and getting conversion tools to convert old-bonkers-software-originally-running-on-valve-processors has turned out to be a tad expensive.

The big surprise (for me) was having a Jovial compiler for an S/390 (or rather an S/360 as it would have been then). AFAIK when it's IBM mainrframe and it's real time it was assembler (which is how NASA got theirs to deal with the Apollo programme).